An image reading apparatus is known which scans the both sides of an original sheet at a time when the original sheet is conveyed so as to acquire electronic image data of the two sides of the original sheet. In a conventional image reading apparatus, there also is an apparatus in which the reading position of front surface of an original sheet is different from that of back surface of the original sheet according to convenience for design.
In the use of an image reading apparatus having two different reading positions for duplex scanning, due to the difference in the front surface reading position and the back surface reading position, the timing at which the scanning on the front surface of a sheet is ended is different from that at which the scanning on the back surface of the sheet is ended. When the image reading apparatus is used for scanning, if an error such as a paper jam occurs in a conveyance path during the conveyance process of an original sheet, then it happens that the scanning on the back surface of an original sheet is not completed even if the scanning on the front surface of the original sheet is completed.
If the error occurs, after eliminating the error, the user places the original sheet on a feed tray again to scan the original sheet again. On this occasion, if the front surface and the back surface of the original sheet are placed reversely for scan, then the arrangement of the content of the original sheet is changed. Thus, the user must be aware of which side of the original sheet should be scanned again as the front surface of the original sheet.